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Comparing functional indexes with non-functional indexes

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Comparing functional indexes with non-functional indexes


Same portion:
1.Index options like UNIQUE and CLUSTER, and access methods like B-Tree, R-Tree and user-defined access methods can apply to both functional and non-functional indexes.

2.Both types of indexes can specify a FILLFACTOR and both can specify storage options that control where the index is created and whether or not it is fragmented.

3.The oncheck utility can be used to validate and repair both functional and non-functional indexes

Different portion:

1.One main difference between functional and non-functional indexes is how they are handled during the CREATE and DROP operations.Functional didn't support ONLINE keyword,which means that an exclusive lock is always placed on the indexed table while a functional index is being created or dropped. All other users are prevented from accessing the table during this time.

functional index:
CREATE INDEX ... ONLINE; <== Not valid
DROP INDEX ... ONLINE; <== Not valid

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Document information

More support for: Informix Servers

Software version: 11.5

Operating system(s): AIX, HP-UX, Linux, Solaris, Windows

Software edition: Enterprise

Reference #: 1415833

Modified date: 21 October 2011